Headlight



, 0. WINSTON.

nnnuern. APPLICATION FILED All. 1- '9"- mm Aug. 17,1920.

: 4 SHEETS-SHEET l- WI T/YESS'ES' INVE/Y 56. fiver/on m on arms/1mm '0.WINSTON.

HEADLIGHT.

APPLICATION FILED ma. z, 19!?- .1,-349,595. Patented Aug. 17, 1920.

4 SHEETS-SEES] 3.

Over/aw Q 3% 4M Min.

0. WINSTON.

- HEADLIGHT. Armenian nun Ill. 2. 1s".

Patuntail Aug. 17 1920.

W1 7NE'66E5 INVENTOE g I aver/on XY/nsfan g 5) Hi6 arrole/vzrs UNITEDSTATES PATENT OFFICE.

HEADLIGHT.

Specification of Letters Patent.

Patented Aug. 17, 1920.

Application filed March 2, 1917. Serial No. 151,931.

To all whom it ma concern:

Be it known that I, OVERTON WINSTON, a-citizen of the United States,residing at Minneapolis and State of Minnesota, have invented certainnew and useful Improvements in Headlights; and I do here y declare thefollowing to be a full, clear, and exact description of the invention,such as will enableothers skilled in the art to which it appefiains tomake and use the same. lighiis and is particularly directed to theprovision of an improved form of lens and to animproved relativearrangement thereof, in respect to a concave reflector and electriclight source within the latter.

In the accompanying drawings which illustrate the invention, likecharacters indicate like parts throughout the several views.

Referring to the drawings:

Fi ure 1 is a vertical section showing a head ight embod ing myinvention 'and whereln a two-fifament light bulb is employed as a meansfor shiftin the light source from the axis of the re ector to a pointvertically above said axis;

Fig. 2 is an elevation looking at the inner face of the lens;

Fig. 3 is a fragmentary view in inner face elevation showing, on anenlarged scale, one of the prismatic sections of the lens;

Fig. 4 is a section on line 4-4 pf Fig. 3;

Figs. 5, 6 and 7 are transverse sections taken on the lines 55, 66, and7--7 of Fig. 3;

ig. 6 is an enlargement of the prism shown in Fig. 6, but indicating thetravel of the ray of light in passing thereto, therethrough andtherefrom; and 4 Fig. 8 is a view corresponding to Fig. 1, but showing aheadlight having a single filament light bulb.

Of the parts of the headlight, the numeral 9 indicates the casing thenumeral 10, the clamping ring thereof, the numeral-11 the concavereflector, the numeral 12 the electric 1i ht bulb and the numeral 13 thelens. The reflector 11 is preferably a hyperbolic reflector and it isrovided with an axial assa e through w ich the shank of the ight ulb 12projects and is held by a suitable support. This bulb support, so far asthis invention is concerned may be of any suitable construction, but asshown, compresent invention relates to headprises a shank engagin sleeve14 and, a tubular socket l5 screwe into a flanged hub 16secured to thehack of the reflector.

in the county of Hennepin s. The bulhshowniin Fig. 1 is atwo-filamentbulb the one filament having its hot spot at a and the other having itshot spot at b. The point a 'is at the axis of the reflector andpreferably also at the focal center thereof. ,The point I) is verticallyabove the axis of the reflector. By means of a three-lead circuit 17,18, and 19, which includes a battery 20, and switches 21 and 22, eitherof the two filaments a and b may: at will, be energized and used as thelight source of the headlight. These electric connections are more fullydisclosed in my pendiiif application S. N. 86,852, filed of datearch 27,1916, and entitled Headlights.

In the headlight illustrated in Fig. 8, the light bulb 12 is providedwith a single filament 0, the hot spot of which is at the axis of thereflector and preferably also at the focal center thereof. This filamentis connected to abattery or source of electrical energy 23, by leads 24in one of which is a switch 25.

We will now consider the novel construction of the lens, the preferredform of which is illustrated in the drawings and which, described indetail is as follows:

One face of the lens, preferably its inner face, is formed withprismatic surfaces that extend. horizontally across that face of thelens. The beveled surface of all of the prisms diverges downwardly fromthe plane of-the lens but the different prisms have a different bevel.The greatest bevel is approximately at a horizontal line that intersectsthe axis of the lens and headlight, and in the lens illustrated, thesaid horizontal prism that intersects said axis has a downwarddivergence or bevel of eighteen degreesto the plane of the lens. Thebevel of the successive prisms in directions bothvertically upward andvertically downward from the said horizontal line or plane of the axisof the lens, progressivel decreases, preferably, in a constant or er ofsuccession. For example, the variation in the bevel of successive prismsmay be, as indicated by the small numerals marked adjacent to the righthand extremities thereof on Fig. 2 by reference to which it will benoted that the uppermost and lowermost prisms have a bevel of onlyone-half degree of the extreme upper and to the plane of the lens, andthe bevel of the upper prisms increases onehalf degree, each over theother to the horizontal plane of the axis of the lens, while the prismsthat are below said horizontal lane progressively increase in likemanner in an upward direction.

Each particular prism, in a horizontal direction, referably has aconstant bevel. For examp e, if it has an angle of eighteen degrees atthe axis of the lens, it Wlll have the same bevel at its extremities, orat the margin of the lens, but in some instances the angle in eachparticular prism may vary in a horizontal direction, as for exam le, inmy companion a lication filed of ate March 3rd, 1917 S. 152,228, andentitled Headlights.

By reference to Fig. (5, it will be noted that a ray of light in passingthrough one of the prisms, Wlll be given a downward deflection. This, ofcourse has the eneral effect of producing a downward de ection of thelight beam. In view of the increasing bevel of the prisms nearest to thehorizontal plane of the axis of the reflector it is obvione that thegreatest downward deflection will be given to the most intense lightrays that come from the back of the reflector. This, of course, isdesired in order to throw the greater part of the light onto the road.

In Fig. 1, the lighter ray lines indicate the light rays when t e li htsource is at a and the heavier ray lines, the rays when the lightsourceis at b; and it will be observed that the beam is given greaterdownward deflection when the light source is at b than when the lightsource is at a. This is especially true in respect to the more intenserays from the back of the reflector and in fact, some lower rays will beslightly higher when the light source is at 6 than when the light sourceis at a.

Obviously, the best light beam for country road driving is produced whenthe light source is at a and the best light beam or cit street drivin isproduced when the lig t source is at It is not desirable to give thisgreat downward deflection to the less intense rays from the upperportion of the reflector as is iven to t e more intense rays from thebac ofthe reflector. It is desirable to get a maximum amount of intenserays on the road, but it is also desirable to diffuse some of the lessintense light rays 50 as to light up objects above the road and at thesides of the road, and for this reason, the prisms nearest to thehorizontal plane of the axis of the reflector are given greatest beveland those nearest the top and p ferablyalso those nearest the bottom aregiven decreased or less an 1e.

In theuse of a bee light with an ordinary reflector adjusted so as tothrow approximately the lowerhalf of the light beam upon the ground,which is quite a common atrangement, the lower half of the light beamwill be distributed over many hundreds of square feet of road surface,and er unit of surface, the road will be given ut a. ver

small percentage of light as compared with the amount of ight thrownupon a vertical object in the road, by the up er half of the light beam.This is a resut just reverse from that desired. An ideal arrangementwould be one in which there would be at least as much light, per unit ofsurface, thrown upon the road as there would be u on a vertical objectabove the road; an such an arrangement, obviously, requires very muchthe greater part of the light beam to be distributed on the ground and avery minor part of the light beam to be difi'used abcive the road. Thisideal result is closel approximated by the use of the improve lens abovedescribed, which, as already stated produces very great downwarddeflection oi the more intense rays of the light beam and diffuses some,or a minor part, of the less intense light rays above the road.

It is important to note that, in the applicants lens, the reverseprogression from an intermediate prism, in the order of succession, isthe same in allplanes that intersect the several prisms at a right anIs. For instance, in the lens shown in the rawings, the

. order of succession of the progression is ste by step from the oneprism to the other, an this same order is present in all of the verticalcross sections through the lens.

What I claim is:

l. A lens for headlights having parallel prisms beveled in the samegeneral direction said prisms having, in respect to the basa surface ofthelens, bevels, the an les of which, as among the successively a jacentprisms, decrease, step by step, in reverse order, in opposite directionsfrom an intermeiliate prism located at the diameter of the ens.

2. A lens for headlights having parallel prisms beveled in the samegeneral direction said prisms having, in respect to the base surface ofthe lens, bevels, the angles of which, as among the successivelyadjacent prisms, decrease, step by step, in reverse order, in oppositedirections from an intermediate prism, located at the diameter of thelens, each individual prism having substantially the same bevel in allof its cross sections. 7

3. A lens for headlights having parallel prisms beveled in the samegeneral direction said prisms having, in respect to the basal surface ofthe lens, bevels, the an Ice of which, as among the successivelyadjacent prisms, decrease, step by step, in reverse order, in oppositedirections from an intermediate rlsm, located at the diameter of thelens, t e prisms that are equidistant from said intermediate prism,having the same angle to the basal surface of the lens.

4. A lens for headlights having parallel prisms beveled in the samegeneral direction, said prisms having, in respect to the basal surfaceof the lens, bevels, the angles of which, as among the successivelyadjacent prisms, decrease, step by step, in reverse order, in oppositedirections from an intermediate prism, located at the diameter of thelens, each individual prism having substantially the same bevel in allof its cross sections, the prisms that are equidistant from saidintermediate prism, having the same an le to the basal surface of thelens.

11 testimon whereof I alfix my signature in presence 0 two witnesses.

OVERTON WINSTON.

Witnesses CLARA DEMAREST, BERNIGE G. WHEELER.

